Field of the Invention
The present invention relates to a damper structure, in particular to a damper structure utilizing the linear displacement of the transmission shaft for generating magnetic resistance.
Description of the Prior Art
Conventionally, dampers are utilized in training equipments for body exercise or for rehabilitations to increase the resistance for operating a mechanism of the training equipment. A common damper is a pressure cylinder, for example, a hydraulic cylinder or a pneumatic cylinder. A piston shaft of the cylinder is connected to the mechanism. The reciprocal displacement of the mechanism drives the piston shaft to move. The moving of the piston shaft is retarded by the resisting force from the fluid in the cylinder. In other words, a user has to apply much more forces for driving the mechanism of the training equipment to achieve the training purposes.
However, in the conventional design, the repeated displacements of the piston shaft increase wearing between the fluid in the cylinder and an oil sealing member of the cylinder so as to increase the temperature of the cylinder increases. As a result, the oil sealing member of the cylinder would be solidified or even broken. Eventually, the fluid may leak from the cylinder to reduce the damping performance. On the other hand, the change of the temperature of the fluid also changes the physical properties of the fluid. As a result, the damping performance capable of being provided by the cylinder is not stable. Consequently, the damping performance of the training equipment cannot be standardized.